Remember that people learn in different ways, by listening, visually, by reading, and through experience.
Give the information in multiple formats — then you’ll hit the right method for more people. And repetition helps too.
And, if you make posters, have them laminated and put them up on an easel, they’ll have a chance to read them when they have a moment, and you’ll have a prop. with visual cues for you to talk about.
This way, you’ll won’t forget anything, and the pictures will ensure everyone knows what you’re talking about. One of my posters shows pictures of each of the different firing methods for metal clay. So as I talk about the firing methods, I can show a picture of each one.
And remember to give people bathroom breaks. ; )